Center-feed rolls that consist of webs of paper, nonwoven, or other sheet-like materials which are perforated such that the webs can be separated into individual sheets are well-known to those skilled in the art. The roll is often installed in a dispenser with the axis of the roll being vertical, and the sheet-like material is fed from the center of the roll out of the dispenser through an aperture, usually in the base of the dispenser. This type of roll and dispenser is often found in public restrooms, gas station pump areas, and in hospitals and industry, either for use as a dispenser for hand towels or for tissues or towels for general cleaning use.
EP-0865247-B1 to King discloses a double-wound center-feed roll and a dispenser for supporting the roll having an aperture and a base in the dispenser which is provided with a rim which projects into the center of the roll in use. It describes a center-feed roll formed from two webs each having lines of weakness which allow the webs to be separated into a plurality of individual sheets. The lines of weakness of one web are offset from those of the other such that in use the sheets can be dispensed singly from alternate webs. Thus, it provides a double-wound center-feed roll which allows single-sheet dispensing. In use, both webs feed through the aperture of the dispenser, with one web protruding further than the other due to the offset lines of weakness. A user grips and pulls the outermost web, and the friction between it and the aperture causes the next line of weakness in that web to break when it is at or near the aperture such that a single sheet is dispensed. As one web is being pulled from the dispenser and a sheet detached, the other web is also being drawn out from the dispenser. Because the lines of weakness are offset, when the line of weakness of one web breaks, the first sheet of the next web is already protruding from the dispenser. Thus, a well-presented and untouched sheet is available for the next user.
Dispensing performance of the above-described double-wound center-feed roll can be impaired if the orientation of the dispensing webs is reversed. Double-wound center feed rolls are made, as described above, with an inner web and an outer web. The inner web is positioned directly adjacent to the core or the center of the roll. The outer web is separated from the core or center of the roll by the inner web. Web orientation reversal occurs when one complete circumference of the inner web is removed without removing any portion of the outer web. When this occurs, the inner web becomes the outer web and the outer web becomes the inner web.
Web orientation reversal impairs dispensing performance because it can change the relationship of the offset perforations between the inner and the outer webs. When the inner web and the outer web are maintained in the proper relationship, i.e., the inner web remains the inner web and the outer web remains the outer web, the perforations in the inner and outer webs are offset. If the webs reverse, the perforations of the new inner and new outer webs may not have the proper spacing with respect to one another and dispensing may become more difficult or stop altogether.
One method of reducing the incidence of web orientation reversal is to lightly crimp the inner web to the outer web prior to winding the inner and outer web into a roll. Processes for lightly crimping layers together are known in the art. Lightly crimping the inner and outer layers associates the layers together making it less likely for a user to reverse the two layers. However, the light crimping increases the dispensing force required to separate one web from the other and is likely to increase the incidence of streaming, a dispensing problem that occurs when an individual sheet fails to separate, but rather, continues to pull an excessively long section of attached sheets from the dispenser.
Therefore, there is a need for a double-wound center-feed roll in which single sheets can be dispensed with both reduced opportunity for reversal of the inner and outer webs and reduced incidence of streaming. Additionally, there is a need for a process for manufacturing the same.